SingleAxisGeometryReader.swift (2209B)
1 /* MIT License 2 * Copyright (c) 2020 Canis from @wooji 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a copy 5 * of this software and associated documentation files (the "Software"), to deal 6 * in the Software without restriction, including without limitation the rights 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 8 * copies of the Software, and to permit persons to whom the Software is 9 * furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice shall be included in all 12 * copies or substantial portions of the Software. 13 * 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 20 * SOFTWARE. 21 */ 22 import SwiftUI 23 import UIKit 24 25 struct SingleAxisGeometryReader<Content: View>: View { 26 var axis: Axis = .horizontal 27 var alignment: Alignment = .center 28 let content: (CGFloat) -> Content 29 30 private struct SizeKey: PreferenceKey { 31 static var defaultValue: CGFloat { 10 } 32 static func reduce(value: inout CGFloat, nextValue: () -> CGFloat) { 33 value = max(value, nextValue()) 34 } 35 } 36 37 @State private var viewSize = SizeKey.defaultValue 38 39 var body: some View { 40 content(viewSize) 41 .frame(maxWidth: axis == .horizontal ? .infinity : nil, 42 maxHeight: axis == .vertical ? .infinity : nil, 43 alignment: alignment) 44 .background(GeometryReader { proxy in 45 Color.clear.preference(key: SizeKey.self, 46 value: axis == .horizontal ? proxy.size.width 47 : proxy.size.height) 48 }) 49 .onPreferenceChange(SizeKey.self) { viewSize = $0 } 50 } 51 }